Treatment of wood tar distillates



May I6, 1950 R. H. Rosl-:NWALD TREATMENT 0F WOOD TAR DISTILLATES Filed April 29, 1947 QG Qu@ engl wnom @nach IN VEN TOR.

Rober! H, Hosenwa/d Ahorney atented May 16, "19:50

TREATMENT OF WGOD TAR DISTILLATES Robert H. Rosenwald, Western Springs, Ill., assignor to UniversalA Oil Products Company, Chicago, Ill., a corporation of Delaware Application April 29, 1947-,I Serial No. 744,765l v 1 Claim. 1

This invention relates 'to the treatment of wood tar distillates and more particularly of a method of improving the inhibitor properties thereof.

Wood tai` distillates and particularly selected fractions thereof have been used as inhibitors to prevent the undesirable deterioration of unstable organic substances and particularly cracked gasoline. This inhibitor is used in small amounts which generally are below 1% by weight and more particularly are usually within the range of from about 0.001% to about 0.1% by weight.

However, it has been found that, while this inhibitor is highly satisfactory in certain gasolnes, it does have objections when used in other gasolines. Some of these objectionable properties are potencies lower than desired, a tendency on the part of the inhibitor to discolor, and solubilities in gasoline lower than desired. The present invention is directed to a method of improving these properties of wood tar distillates.

In a broad embodiment the present invention relates to a method of improving the properties of wood tar distillate which comprises treating the wood tar distillate with an alkaline solution, separating neutral oil from an alkaline solution and separately withdrawing the same, further separating said alkaline solution into a fraction soluble in the alkaline solution and a fraction insoluble therein, treating said soluble fraction with carbon dioxide, and recovering therefrom an inhibitor of improved properties.

Another objection to the use of wood tar distillate as an inhibitor in gasoline is that the inhibitor does not prevent the black water test.

It has been found that treating wood tar distillate in accordance with the teachings of the present invention will produce an improved inhibitor which will not give the black water test. It can readily be seen that this is a major advantage from the viewpoint of the reiiner who uses this inhibitor to stabilize his gasoline.

The novelty and utility of the present invention is further illustrated in the accompanying diagrammatic flow drawing which illustrates one specific embodiment of the invention.

While the present invention may be used for the treatment of wide boiling range wood tar distillate, it is particularly applicable to the treatment of selected fractions boiling within the range of from about 250 to about 310 C. The wood tar distillate is introduced to the process through line I into extraction zone 2 where it is contacted with a caustic solution introduced through line 3. The extraction and reaction in zone 2 is generally effected at a temperature of 2 from about C. to about 120L7 C. Extraction zone 2 may comprise any suitable zone for effecting the desired contacting of the wood tar distillate and alkaline solution.

A neutral oil is eparated in extraction zone 2 and is removed therefrom through line 4. The soluble and reacted material in zone 2 is removed therefrom through line 5 and is preferably cooled to a temperature below about 70 C. in cooler 6, and then is directed through line 1 to separation zone 8.

An insoluble fraction is separated in Zone 8 and may be removed therefrom through line 9, while a fraction soluble in the alkaline solution is removed from zone 8 through line I0 and is directed to neutralization zone II. As an essential feature of the present invention, neutralization of the soluble fraction introduced to zone I I must be effected with carbon dioxide, as it has been found that the use of mineral acids for this purpose results in a product which does not possess the high inhibitor potency and which will give the black water test; whereas the use of carbon dioxide unexpectedly produces an inhibitor of higher potency and one that will not give the black water test.

Carbon dioxide is introduced to zone l I through line I2, and excess carbon dioxide may be removed therefrom through line I3. An aqueous phase is removed from zone II through line I4, while the improved inhibitor product is removed therefrom through line I5.

The novelty and utility of the present invention is further illustrated by the following example, although with the understanding that the invention is not limited to the specic example described.

A wood tar fraction boiling within the range of from about 250 to about 310 C. was treated at C. with a 15% caustic solution in an amount of 30 grams of sodium hydroxide per 100 grams of wood tar distillate. The extract was washed with benzene to remove neutral oil, and then was cooled and allowed to settle into a soluble fraction and a fraction insoluble in the alkaline solution. The soluble fraction was then treated with carbon dioxide and a nal product was separated from an aqueous phase.

A Pennsylvania cracked gasoline having a blank induction period of about 100 minutes was used in these tests. When added in an amount of 0.05% by weight the wood tar distillate prior to treatment in accordance with the present invention increased the induction period of the cracked gasoline to 765 minutes. On the other hand, 0.05% by Weight of the inhibitor produced as hereinbefore set forth, increased the induction period of another sample of the cracked gasoline to 1020 minutes. In addition, the improved inhibitor of the present invention was of increased solubility in gasoline, was more color stable and was improved insofar as the black water testis concerned.

I claim as my invention:

A method of improving the inhibitor properties of Wood tar distillate which comprises extractinga wood tar distillate boiling fromA about 250 to about 310 C. with caustic at a temperature of from about 80 to about 120 C., separating neutral oil from the resultant caustic phase and separately withdrawing the same, cooling said caustic phase to a temperature below. about .70920.v

and separatingY the same into a fraction soluble `in caustic and a fraction insoluble therein, treating said soluble fraction with carbon dioxide and recovering therefrom an inhibitor of improved potency.

ROBERT H. ROSENWALD.

REFERENCES CITED# The following references are of record in the le of this patent:

UNITED STATES PATENTS 

